A general organometallic vapor-phase epitaxial system is commonly used for the growth of IIIA-VA compounds. For a nitride epitaxy, it is required to use ammonia as a reaction source of nitrogen. However, ammonia is reactive only under high temperature. As the growth temperature is increased, the demand for the saturated vapor pressure of nitrogen for the growth of gallium nitride is increased. It brings about an increased depletion of ammonia but the effective reaction amount of nitrogen does not increase. In addition, the epitaxial system using ammonia has some disadvantages as follows:
1. During the growth of P-type III-V compound, the coverage by hydrogen is occurred, resulting in that P-type III-V compound is under a high isolated state. Therefore, it needs another treatment for recovering the P-type electrical conductivity. PA1 2. Ammonia easily causes a comsumption of graphite and vacuum-required oil, and a damage of the vacuum tube and the system so that it is an uneasy task to maintain the system. PA1 1. After the VA elements leave the electron cyclotron resonance, they will easily return to the molecule state (e.g. N.sub.2). Therefore, the effective amount for forming the IIIA-VA compound is quite less than its consumed amount of the initial reactant. PA1 2. The wafer substrate can not be heated to a higher temperature so that the crytallization of the epitaxial layer is not good enough.
In another organometallic vapor-phase epitaxial system using the electron cyclotron resonance (ECR), IIIA and VA elements are provided from different tubes and then react with each other to produce an epitaxial growth on the surface of the wafer substrate. However, it still has some defects:
Therefore, it is desirable to develop a device or method to solve the problems encountered by the applicant.